1. Field of the Invention
The present invention relates generally to valve stem caps. More specifically, the present invention relates to valve stem caps that lock so as to prevent theft thereof. Additionally, the present invention relates to methods for installing and removing a valve stem cap from a valve stem.
2. Background of Related Art
Valve stems have long been used to facilitate the inflation and deflation of inner tubes, which are typically used in tires, as well as of so-called “tubeless” tires. Typically, a valve stem is a generally cylindrically shaped member that includes an external portion which protrudes from a wheel on which a tire has been installed and an internal portion that communicates with the interior of an inner tube or the tire. A valve, which controls the flow of air into and out of the valve stem and, thus, the inner tube or tire with which the valve stem communicates, is typically located at or near the exposed end of the external portion of the valve stem. In addition, a valve stem typically includes spiral threading on the exterior thereof, adjacent to the exposed end thereof. The threading of a valve stem facilitates the installation of a valve stem cap with complementary internal threading over the exposed portion of the valve to protect the valve and to further prevent air from escaping from the inner tube or tire.
Conventional valve stem caps are small, plastic or metal members that merely cover the end of a valve stem until access to the valve therein is desired. Often, such members include a series of longitudinally extending ridges thereon or other surface roughness features to facilitate the manual installation of the valve stem cap onto a valve stem, as well as its removal from the valve stem.
More aesthetically pleasing, or decorative, valve stem caps, which are also commonly referred to as “designer” valve stem caps, have been designed to improve the appearance of the valve stem, as well as that of the wheel from which the valve stem protrudes. Designer valve stem caps may have a shape or finish which matches that of the wheel adjacent to which they are to be used. Sometimes, designer valve stem caps include indicia, which may match other indicia on the vehicle (e.g., automobile, motorcycle, bicycle, etc.) or other apparatus with which they are used. Such features may increase the desirability of designer valve stem caps to others, which, combined with the conventional ease with which such caps may be removed, as well as with their high value relative to that of conventional valve stem caps, may result in theft thereof.
Consequently, locking, or tamper-resistant, valve stem caps have been developed. U.S. Pat. No. 5,630,687, issued to Robinson on May 20, 1997 (hereinafter “Robinson”), and U.S. Pat. No. 6,062,787, issued to Maddalena on May 16, 2000 (hereinafter “Maddalena”) describe a couple of examples of tamper-resistant valve stem caps.
The tamper-resistant valve stem cap of Robinson includes an inner cap member, which is configured to be disposed over the end of a valve stem, and a decorative outer sleeve member, which is configured to be placed, by longitudinally sliding the same, over the inner cap member and secured thereto once the inner cap member is in place upon a valve stem. Robinson describes that a small set screw, which, when rotated, moves along a threaded aperture of the outer sleeve member, may be placed in a securing position, wherein an end of the set screw is inserted into a corresponding recess of the inner cap member, or a removal position, wherein the set screw is moved away from the inner cap member a sufficient distance to permit longitudinal sliding of the outer sleeve member relative to the inner cap member. The requirement of a tool to install the valve stem cap of Robinson on a valve stem is somewhat undesirable. Also, if the set screw does not stay in the proper position, the decorative portion of the Robinson valve stem cap may fall off of the inner cap member thereof and be lost. Moreover, due to the relatively small size of the set screw, handling thereof may be undesirably difficult if the set screw becomes filly removed form the threaded aperture of the outer sleeve member. Further, the base of the protruding portion of a valve stem remains exposed and, thus, prone to damage from the elements, bending, and flexing when a valve stem cap of the type described in Robinson is used thereon.
Maddalena also describes a valve stem which includes an outer sleeve member. The outer sleeve member of the valve stem cap of Maddalena is a hollow cylindrical member which is secured to the inner cap member thereof in such a way that the entire outer periphery of the inner cap member is surrounded by the outer sleeve member. Moreover, the outer sleeve member and the inner cap member of the tamper-resistant valve stem cap of Maddalena may be rotated independently of one another; rotation of the outer sleeve member will not result in rotation of the inner cap member. Accordingly, an upper surface of the inner cap member, which is exposed through the outer sleeve member, includes indents that are configured to be engaged by a key which corresponds to the valve stem cap. Thus, the valve stem cap may only be installed upon a valve stem by rotating the inner cap member with the key. Unfortunately, the inner cap member cannot be rotated manually. Therefore, the tamper-resistant valve stem cap of Maddalena cannot even be partially installed upon a valve stem or removed therefrom without the key. Further, like the tamper-resistant valve stem cap of Robinson, the valve stem cap of Maddalena is not configured to surround or protect the base of the protruding portion of a valve stem.
The inventor is not aware of a valve stem cap that substantially covers and protects a base of a protruding portion of a valve stem, or of a locking, or tamper-resistant, valve stem cap that may be installed upon a valve stem without requiring the use of a key or other tool.